The combination of sofosbuvir and velpatasvir (SOF/VEL) for 12 weeks was
authorized for use in patients without cirrhosis or with compensated
cirrhosis (Child-Pugh A), and in combination with ribavirin (RBV) for
patients with decompensated cirrhosis (Child-Pugh B or C). SOF/VEL is
also the first single tablet regimen approved for the treatment of
patients with HCV genotype 2 and 3, without the need for RBV. Physicians
also have the flexibility to consider the addition of RBV for genotype 3
infected patients with compensated cirrhosis.

The Marketing Authorization follows an accelerated review procedure by
the European Medicines Agency, reserved for medicinal products expected
to be of major public health interest. It allows for the marketing of
SOF/VEL in all 28 countries of the European Union.

SOF/VEL is Gilead’s third sofosbuvir-based treatment to be granted
Marketing Authorization by the European Commission for the treatment of
chronic HCV infection. Sofosbuvir-based regimens are recommended by
global guidelines across all HCV genotypes and disease severities.
Today, nearly one million patients worldwide have been prescribed a
sofosbuvir-based regimen.

“Built on the foundation of sofosbuvir, SOF/VEL offers a highly
effective and tolerable choice which is protease inhibitor free and
ribavirin free for the majority of patients. For the first time we have
a once-daily single tablet treatment option which works across all
genotypes including genotype 3, which is often the least responsive to
treatment,” said Professor Stefan Zeuzem, Professor of Medicine and
Chief of the Department of Medicine at the J.W. Goethe University
Hospital, Frankfurt, Germany and an ASTRAL-1, 2 and 3 study
investigator. “This approval marks a significant advance in the
treatment of HCV and is an important step in our efforts to achieve
elimination of the disease throughout Europe.”

The authorization of SOF/VEL is supported by data from four Phase 3
studies, ASTRAL-1, ASTRAL-2, ASTRAL-3 and ASTRAL-4. In the ASTRAL-1,
ASTRAL-2 and ASTRAL-3 studies, 1,035 patients with genotypes 1-6 HCV
infection, without cirrhosis or with compensated cirrhosis (Child-Pugh
A) received 12 weeks of SOF/VEL. The ASTRAL-4 study randomized 267
patients with genotypes 1-6 HCV infection, with decompensated cirrhosis
(Child-Pugh B) to receive 12 weeks of SOF/VEL with or without RBV or 24
weeks of SOF/VEL alone. The primary endpoint for all studies was the
sustained viral response rate 12 weeks after treatment (SVR12).

John Milligan, Ph.D., President and Chief Executive Officer of Gilead
said, “The burden of hepatitis C across Europe is substantial and
growing rapidly with approximately 15 million people chronically
infected. The European approval of SOF/VEL reflects our continued focus
to bring a cure to all infected patients across the region and we look
forward to working with physicians, healthcare providers and governments
to make it available as quickly as possible.”

Of the 1,035 patients treated with SOF/VEL for 12 weeks in the ASTRAL-1,
ASTRAL-2 and ASTRAL-3 studies, 1,015 (98 percent) achieved SVR12. In
ASTRAL-4, patients with decompensated cirrhosis receiving SOF/VEL with
RBV for 12 weeks achieved a higher SVR12 rate (94 percent) compared to
those who received SOF/VEL for 12 weeks or 24 weeks without RBV (83
percent and 86 percent, respectively.) The most common adverse events in
the four ASTRAL studies were headache, fatigue and nausea, and were
comparable in incidence to the placebo group included in ASTRAL-1.

Sofosbuvir as a single agent was granted marketing authorization in the
European Union on January 16, 2014 under the trade name Sovaldi®.
The fixed-dose combination of sofosbuvir (400mg) and ledipasvir (90mg)
received marketing authorization in the European Union on November 18,
2014 under the trade name Harvoni®.

Epclusa was approved by the U.S. Food and Drug Administration on June
28, 2016 for the treatment of adults with genotype 1-6 chronic HCV
infection.

Important Safety Information

Contraindications include hypersensitivity to the active substances or
to any of the excipients. Co-administration with potent P-glycoprotein
(P-gp) or potent cytochrome P450 (CYP) inducers (e.g. rifampicin,
rifabutin, St. John’s wort [Hypericum perforatum], carbamazepine,
phenobarbital and phenytoin) is contraindicated.

Caution and frequent renal monitoring is recommended for
co-administration with certain HIV antiretroviral treatments (e.g.
tenofovir disoproxil fumarate- and efavirenz-containing regimens).
Safety has not been established in patients with severe renal impairment
(glomerular filtration rate <30ml/min).

Monitoring of digoxin, dabigatran and amiodarone is recommended when
used with sofosbuvir/velpatasvir. For patients on statins dose reduction
should be considered and careful monitoring for statin adverse events
(myopathy and rhabdomyolysis) should be undertaken.

The “interaction with other medicinal products and other forms of
interaction” section of the Epclusa EU Summary of Product
Characteristics (SmPC) should be consulted before starting therapy with
sofosbuvir/velpatasvir.

Sofosbuvir/velpatasvir should not be administered concomitantly with
other medicinal products containing sofosbuvir.

In clinical studies, adverse events were comparable to placebo, with
fatigue, headache and nausea the most commonly reported side effects.

Please refer to the SmPC for further details. The SmPC is available at www.ema.europa.eu.

About Gilead

Gilead Sciences is a biopharmaceutical company that discovers, develops
and commercializes innovative therapeutics in areas of unmet medical
need. The company’s mission is to advance the care of patients suffering
from life-threatening diseases. Gilead has operations in more than 30
countries worldwide, with headquarters in Foster City, California.

Forward-Looking Statement

This press release includes forward-looking statements, within the
meaning of the Private Securities Litigation Reform Act of 1995, that
are subject to risks, uncertainties and other factors, including the
risk that physicians may not see the benefits of prescribing Epclusa.
These risks, uncertainties and other factors could cause actual results
to differ materially from those referred to in the forward-looking
statements. The reader is cautioned not to rely on these forward-looking
statements. These and other risks are described in detail in Gilead’s
Quarterly Report on Form 10-Q for the quarter ended March 31, 2016 as
filed with the U.S. Securities and Exchange Commission. All
forward-looking statements are based on information currently available
to Gilead, and Gilead assumes no obligation to update any such
forward-looking statements.

Full European Summary of Product Characteristics for Sovaldi, Harvoni
and Epclusa are available from the EMA website at www.ema.europa.eu.

Sovaldi, Harvoni and Epclusa are registered trademarks of Gilead
Sciences, Inc. or its related companies.

For more information on Gilead Sciences, please visit the company’s
website at www.gilead.com
or call Gilead Public Affairs at +44 (208) 587-2477.